Vulnerability in openc3 (CVE-2026-42084)
Summary
Vulnerability in openc3 (CVE-2026-42084). Confidential information can be exposed externally. Mitigation: upgrade to 7.0.0-rc3 or later.
Original description
The description as published by the source.
Summary
The OpenC3 password change functionality allows a user to change their password without providing the old password, by accepting a valid session token instead. In assumed breach scenarios, this behaviour can be exploited by an attacker who has already obtained a valid session token, to gain persistence in hijacked account (including admin) and prevent legitimate users from accessing the account.
Details
The design flaw in authentication model (authentication.rb) allows for interchangeable use of password and session tokens for user authentication As old tokens are not revoked upon password reset, an attacker who has obtained a valid session token can continue to authenticate and change the account’s password even after the victim resets it, thereby maintaining persistent control over the compromised account.
PoC
- Attacker is logged in user account with hijacked valid session token, but not knowing the actual password
- Legitimate user, as preventive action, changes his password (password123) using old password (password), that he knows, then establishes new session
- Attacker issues another password change request (in web proxy like Burp) supplying his still valid token as old_password, changing it to attacker-password, from this point preventing any other legitimate users from accessing account
Impact
Persistence…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42084 has been found in openc3.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade openc3 to 7.0.0-rc3 or later.
If unsure, ask your IT team or search "openc3 CVE-2026-42084" on the vendor's site.
CVE-2026-42084 (openc3) — CWE-620 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Patched: 7.0.0-rc3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-620) exists in openc3.
Check the vendor advisory for the affected versions of openc3.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to 7.0.0-rc3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'openc3' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'openc3' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
openc3を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade openc3 to 7.0.0-rc3ステージング環境で 7.0.0-rc3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com